Barcelona (2) v Chelsea (1): The storm-bringer must become a lightning rod. Jose Mourinho, whose Chelsea side are already 2-1 down from the home leg with Barcelona, plans to draw the blasts of rage towards himself at Camp Nou. The brooding history created by last year's tie has been topped up the uproar concerning the dismissal of Chelsea's left-back Asier Del Horno two weeks ago.

"The only thing I can do is go on to the pitch before the warm-up to try and take away a little bit of the good feeling the crowd have," said Mourinho, who got some practice when he was the subject of spitting and verbal abuse on arrival. That, however, was precisely as he intended.

"I was the first one to leave the airport," he explained. "I know what I am doing. After that the players were received without any pressure. Photos, autographs, kisses - everything was easy for them."

The centre-back Ricardo Carvalho seemed to confirm the effectiveness of the strategy. "It was just a few badly behaved people," he said in apparent sincerity. "We shouldn't give it too much importance."

Mourinho was not necessarily sacrificing himself in any case. He has spoken in the past about the time when, as manager of Porto, he went onto the field before kick-off to savour the intensity of an away ground filled with hostile people. For his sake he had better not have lost this taste for being the object of raw feelings.

The trouble is that he may bask in all that yet still be wounded deeply by the way Barcelona perform tonight. Frank Rijkaard's side showed far more artistry than an undermanned Chelsea in London and here should be capable of expressing themselves with even greater flair. The main difficulty for the La Liga side will lie in playing freely when all they need do is avoid defeat. They could even lose 1-0 and progress.

That is just a sliver of encouragement for Chelsea and Mourinho assumes Lionel Messi will aim to be as much of a terror as he was at Stamford Bridge.

"The only way Chelsea can stop him is with 11 men on the field because we must double-mark him," he said. "With 10 men that's not possible because there will be a lot of space for him and he dribbles very well. And if he has a one on one and wins it he can create a lot of danger for us. You need the second man to avert the danger."

Chelsea need to be composed. That knack has been elusive recently and the club have appealed against the red card shown to Arjen Robben at West Bromwich on Saturday. Mourinho feels once again a referee's punishment has been excessive but, as with the Del Horno case, the players have been getting themselves into perilous situations.

Tonight's referee is the experienced Markus Merk and Mourinho challenged the belief that Chelsea start by treating officials as enemies. "You have never seen me before a game saying, 'I don't like the referee, I think the referee is going to do it wrong and help the opposition,'" he declared.

"I always think positive. In this moment I think and believe the referee can perform well, can do his best, can create a clean situation for both teams."

It would be best not to pin too many hopes on so idealised a vision. There are suggestions, for instance, that Mourinho will aim for a hard, protracted battle. In keeping with such an approach it has been rumoured the powerful Didier Drogba will start rather than Hernan Crespo.

William Gallas, who tested a hamstring in his return at West Brom, trained last night and should be the first line of defence against Messi. Frank Lampard, who had a tight hamstring after the first leg, also appeared normal during the session at Camp Nou.

Chelsea will need to touch a level of performance that has been beyond them for a while. The team have lost five of their past seven away games in the Champions League. This season the talent of players such as Robben has been glimpsed but he and others will have to put those abilities on constant show this evening.

Mourinho, winner of the tournament in 2004 and a semi-finalist last year, would be aghast to perish in the last 16. The newspaper El Periodico ran a headline yesterday that translated as "Here comes the bogeyman". Mourinho surely felt flattered.

The real terror is that he could be the one who is given nightmares.

BARCELONA (probable): Valdes; Belletti or Oleguer; Puyol, Marquez, Van Bronckhorst or 16-Silvinho; Deco, Edmilson, Thiago; Ronaldinho, Messi, Eto'o

CHELSEA (probable): Cech; Ferreira, Carvalho, Terry, Gallas; Makelele, Lampard, Gudjohnsen; Cole, Crespo or Drogba, Robben or Duff)

Referee: Markus Merk (Germany)